A New Criterion for the Onset of Liquid Entrainment From a Stratified Two-Phase Region Through a Small Branch

A new criterion has been developed to predict the onset of liquid (heavier fluid) entrainment from a stratified two-phase region through single and dual branches mounted on a vertical wall. This criterion was based on the local instability of the interface between two fluids due to the suction effect associated with the discharging of the lighter fluid. To validate the criterion, a three-dimensional model has been developed to predict the critical height at the onset of liquid entrainment. Comparisons between the theoretical critical heights with the available experimental data demonstrated a very good concurrence between the predicted and the measured values for both single and dual branches. This indicated that the onset of liquid entrainment mechanism occurs due to local flow instability of the interface analogous to Taylor instability.